Recently, there has been much interest in providing three-dimensional (3D) images or videos via a 3D television or a 3D monitor, etc. 3D images or videos may be used in various venues, such as movies, television broadcasting, medical devices, computer or video games, etc. 3D images may be created by using stereo images, i.e., two slightly different images directed at two eyes of a viewer. Recently, 3D image or video providers are paying more and more attention to how to efficiently increase encoding rate of the 3D images or videos and quality of the 3D images or videos.